The U.S. is openly criticizing Moslem nations in the Middle East for saying they are eager to help destroy ISIL (Islamic State in Iraq and the Levant) but do little about it. Too many of these “allies” are much talk and little action. Then there is the delicate subject of Turkey and some Gulf Arab states quietly supporting al Qaeda affiliated Islamic terrorist rebels in Syria because they consider the Iran backed Syrian government more of a threat than al Qaeda. Turkey and these Arab states also see al Qaeda as much preferable to ISIL.
The Saudis and the other Gulf Arab states are mainly concerned with Iranian aggression. Iran has made it very clear that they believe they should control the Moslem holy places in Saudi Arabia and be the dominant military and political power in the region. That means having a veto over Arab diplomatic moves and generally returning to their ancient role of regional superpower. The Gulf Arabs are very hostile to this sort of thing but reluctant to go to war over it because the Iranians have an impressive history of battlefield victories.
In response the Sunni Arab states have tried to use Islamic terrorist groups as a weapon against the “Shia threat. Thus Yemeni Shia rebels blame the Sunni Gulf Arabs of supporting al Qaeda in Yemen. This Islamic terrorist group has always been very hostile towards Shia and the growth of al Qaeda in Yemen was a primary reason for the Yemeni Shia rebelling in the first place. There is some truth to the Yemeni Shia accusations as many Sunni Gulf Arabs do support al Qaeda and have long provided cash donations and recruits. This terrorist support is not government policy with these Gulf States although some Gulf Arab states, like Qatar, have actively supported Islamic terrorist rebels in Libya and Syria.
There is a lot of popular support for Islamic terrorism among Sunni and Shia as it is common to believe that the non-Moslem world is actively at war with the Islam and Islamic terrorists are the only effective weapon to strike back with. This sounds absurd to non-Moslems, especially Westerners and Arab diplomats insist that there is no such terrorist support. But anyone perusing Arab language media immediately sees this support and some of it even shows up in English language versions of Arab media. That despite the fact that the Arab editors of the English language news outlets know that the Arab support for Islamic terrorism is not acceptable to Western audiences and try to remove it from the English language sites. The Iranians understand all this, as do other non-Moslems (like Indians) who have lived next to Moslems for a long time. So when the Yemeni Shia complain of Gulf Arab Sunni support for al Qaeda in Yemen it has a different meaning to other Moslems (who take it as fact) and Westerners (who dismiss it as a paranoid delusion).